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Re: Compressed Library was Re: Compressed LDraw files
avatarJanuary 31, 2013 11:24AM
One reason that zips are larger than compressed tar files is that each file in the zip is individually compressed. For this reason, a zipped tar file will usually be smaller than a zip of the tar file's contents. A tar.gz or tar.bz2 is just full tar file that has been run through gzip or bzip2 compression, so cross-file compression works there.

I'm not sure how 7-zip behaves with respect to cross-file compression, but cross-file compression I would think in theory be possible without requiring all the intervening files to be decompressed in order to get to a specific file in the archive. Doing so might require a great deal more work, though, and might increase the size of the archive.

I just ran a test with zip test code I have at work, and it took around 100 msec to scan the table of contents from the 2012-03 complete.zip and store the information in a std::map. This only needs to be done once at program startup (and again any time the user changes their part library to a different one, of course).
SubjectAuthorViewsPosted
Compressed LDraw files Roland Melkert399January 29, 2013 12:33PM
Re: Compressed LDraw files Tim Gould181January 29, 2013 12:44PM
Re: Compressed LDraw files Travis Cobbs190January 29, 2013 12:49PM
Re: Compressed LDraw files Roland Melkert189January 29, 2013 02:01PM
Re: Compressed LDraw files Tim Gould189January 29, 2013 02:10PM
Re: Compressed LDraw files Ben Supnik207January 29, 2013 10:36PM
Re: Compressed LDraw files Roland Melkert200January 30, 2013 10:52AM
Re: Compressed LDraw files Ben Supnik217January 30, 2013 12:59PM
Re: Compressed LDraw files Allen Smith199January 30, 2013 09:17AM
Compressed Library was Re: Compressed LDraw files Travis Cobbs215January 30, 2013 09:40AM
Re: Compressed Library was Re: Compressed LDraw files Philippe Hurbain195January 30, 2013 09:49AM
Re: Compressed Library was Re: Compressed LDraw files Allen Smith185January 30, 2013 08:43PM
Re: Compressed Library was Re: Compressed LDraw files Travis Cobbs190January 30, 2013 10:27PM
Re: Compressed Library was Re: Compressed LDraw files Roland Melkert214January 31, 2013 09:55AM
Re: Compressed Library was Re: Compressed LDraw files Travis Cobbs210January 31, 2013 11:01AM
Re: Compressed Library was Re: Compressed LDraw files Roland Melkert201January 31, 2013 11:07AM
Re: Compressed Library was Re: Compressed LDraw files Travis Cobbs205January 31, 2013 11:24AM
Re: Compressed Library was Re: Compressed LDraw files Ben Supnik201January 31, 2013 12:26PM
Re: Compressed Library was Re: Compressed LDraw files Roland Melkert208January 31, 2013 01:09PM
Re: Compressed Library was Re: Compressed LDraw files Steffen259February 02, 2013 05:34PM
Re: Compressed Library was Re: Compressed LDraw files Tim Gould222January 31, 2013 04:02PM
Re: Compressed LDraw files Roland Melkert218January 30, 2013 10:57AM
Re: Compressed LDraw files Ben Supnik209January 30, 2013 01:15PM
Re: Compressed LDraw files Roland Melkert206January 30, 2013 02:07PM
Re: Compressed LDraw files Allen Smith177January 30, 2013 08:39PM
Re: Compressed LDraw files Roland Melkert211January 31, 2013 01:06PM
Re: Compressed LDraw files Travis Cobbs211January 31, 2013 01:59PM
Re: Compressed LDraw files Travis Cobbs195January 29, 2013 12:46PM
Re: Compressed LDraw files Roland Melkert185January 29, 2013 01:57PM
Re: Compressed LDraw files Steffen195January 29, 2013 03:23PM
Re: Compressed LDraw files Travis Cobbs219January 29, 2013 04:17PM
Re: Compressed LDraw files Roland Melkert215January 30, 2013 10:49AM
Re: Compressed LDraw files Steffen183February 02, 2013 05:33PM



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